Volume 22, Number 3—March 2016
Research
Encephalitis, Ontario, Canada, 2002–2013
Alyssa S. Parpia1, Ye Li, Cynthia Chen, Badal Dhar, and Natasha S. Crowcroft
Table 1
Encephalitis incidence rates, Ontario, Canada, 2002–2013
| Year | Total population (95% CI) | Incidence (95% CI)* |
||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Sex |
Age group, y |
|||||||||
| M | F | <1 | 1–4 | 5–19 | 20–44 | 45–64 | ≥65 | |||
| 2002 | 6.0 (5.6–6.6) | 6.4 (5.6–7.2) | 5.7 (5.0–6.4) | 10.3 (4.1–17.6) | 6.1 ( 4.0–8.5) | 4.7 (3.8–5.7) | 3.6 (3.0–4.3) | 6.6 (5.5–7.7) | 14.1 (12.1–16.4) | |
| 2003 | 3.9 (3.6–4.3) | 4.2 (3.6–4.7) | 3.8 (3.3–4.2) | 6.9 (3.1–12.3) | 6.3 (4.3–8.5) | 3.6 (2.8–4.4) | 2.3 (1.9–2.8) | 4.3 (3.5–5.0) | 7.6 (6.2–9.1) | |
| 2004 | 3.7 (3.3–4.0) | 3.5 (3.0–4.0) | 3.9 (3.4–4.4) | 18.7 (12.0–26.2) | 4.6 (2.9–6.4) | 2.9 (2.3–3.6) | 2.6 (2.1–3.0) | 4.0 (3.4–4.8) | 5.7 (4.6–6.9) | |
| 2005 | 4.0 (3.6–4.3) | 4.2 (3.7–4.7) | 3.8 (3.3–4.3) | 9.0 (4.5–14.2) | 5.3 (3.5–7.3) | 2.7 (2.1–3.4) | 2.5 (2.1–3.0) | 4.5 (3.8–5.3) | 8.0 (6.6–9.4) | |
| 2006 | 3.8 (3.5–4.2) | 4.3 (3.8–4.8) | 3.3 (2.9–3.8) | 10.2 (5.1–16.0) | 3.8 (2.2–5.4) | 2.9 (2.2–3.6) | 2.6 (2.1–3.7) | 3.9 (3.2–4.6) | 7.9 (6.7–9.3) | |
| 2007 | 3.9 (3.5–4.2) | 4.4 (3.9–4.9) | 3.4 (3.0–3.9) | 11.0 (5.9–16.8) | 5.9 (3.9–8.1) | 2.7 (2.1–3.4) | 2.6 (2.2–3.1) | 4.3 (3.6–5.0) | 7.1 (5.8–8.3) | |
| 2008 | 3.9 (3.6–4.3) | 4.6 (4.1–5.1) | 3.3 (2.8–3.2) | 12.1 (7.1–18.2) | 4.5 (2.9–6.2) | 2.8 (2.2–3.5) | 2.8 (2.4–3.3) | 4.2 (3.5–4.9) | 6.9 (5.6–8.1) | |
| 2009 | 4.0 (3.7–4.3) | 4.4 (3.9–4.9) | 3.6 (3.2–4.1) | 10.0 (5.0–15.7) | 6.5 (4.4–8.8) | 2.7 (2.1–3.4) | 2.8 (2.3–3.2) | 3.8 (3.2–4.4) | 7.8 (6.5–9.1) | |
| 2010 | 4.0 (3.6–4.3) | 4.1 (3.6–4.6) | 3.8 (3.4–4.3) | 5.7 (2.1–10.0) | 6.5 (4.4–8.7) | 3.2 (2.5–3.9) | 2.8 (2.3–3.3) | 4.1 (3.5–4.7) | 6.8 (5.6–8.0) | |
| 2011 | 4.7 (4.3–5.0) | 5.0 (4.5–5.6) | 4.3 (3.8–4.8) | 8.6 (4.3–13.6) | 6.1 (4.2–8.1) | 3.1 (2.4–3.8) | 2.9 (2.4–3.4) | 5.5 (4.7–6.2) | 8.5 (7.2–9.9) | |
| 2012 | 5.4 (5.0–5.8) | 5.8 (5.2–6.4) | 4.9 (4.4–5.5) | 12.1 (6.4–18.5) | 6.1 (4.2–8.1) | 4.4 (3.6–5.2) | 3.3 (2.8–3.8) | 5.4 (4.8–6.2) | 10.5 (9.1–12.0) | |
| 2013 | 4.6 (4.2–5.0) | 4.8 (4.3–5.3) | 4.4 (3.8–4.9) | 14.1 (8.5–20.4) | 6.8 (4.7–8.9) | 3.4 (2.7–4.3) | 2.7 (2.2–3.1) | 4.4 (3.8–5.1) | 9.3 (8.0–10.6) | |
| Overall | 4.3 (4.2–4.4) | 4.6 (4.4–4.8) | 4.0 (3.8–4.1) | 10.7 (9.1–12.1) | 5.7 (5.2–6.3) | 3.2 (3.0–3.4) | 2.8 (2.6–2.9) | 4.4 (4.3–4.7) | 8.3 (7.9–8.6) | |
*Incidence is number of cases/100,000 persons. 95% Cis were calculated through bootstrap resampling encephalitis case counts for each age, sex, and year by using 4,000 repetitions.
1Current affiliation: Yale School of Public Health, New Haven, Connecticut, USA.
Page created: February 18, 2016
Page updated: February 18, 2016
Page reviewed: February 18, 2016
The conclusions, findings, and opinions expressed by authors contributing to this journal do not necessarily reflect the official position of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors' affiliated institutions. Use of trade names is for identification only and does not imply endorsement by any of the groups named above.